1db.createCollection("people", {
2   validator: {
3      $jsonSchema: {
4         bsonType: "object",
5         required: [ "name" ],
6         properties: {
7            name: {
8               bsonType: ["string"],
9               description: "must be a string"
10            },
11            friends: {
12               bsonType: ["array"],
13               items : { bsonType: ["string"] },
14               minItems: 0,
15               maxItems: 10,
16               description: "must be a array of string and max is 10"
17            }
18         }
19      }
20   }
21});